Isotropic graphite is designed to reduce the stress from Li+ insertion and extraction [1]. Making it more stable and thus improving lifetime.
By introducing isotropic technology, lithium ions can be inserted into the graphite channel from any angle, which in turn greatly increases the charging speed.
CATL [2]
Wu et al [1] describe the process of making the isotropic graphite spheres and the next step of carbon coating them to improve the electrical conductivity.
Carbon coated isotropic natural graphite spheres (INGS/C) were successfully prepared by spray granulation using superfine natural graphite powders as starting materials. The INGS/C composite is composed of small graphite flakes packed in disordered orientation [1].
Compared with spherical natural graphite (SNG) and isotropic natural graphite spheres (INGS), the INGS/C electrode exhibits:
- higher better rate capability
- improved cycling stability
The improved electrochemical performance is attributed to:
- isotropy and porosity
- helps electrolyte permeation
- alleviates capacity fade caused by stress concentration during the deep insertion and extraction of Li+
- carbon coating
- improves the electrical conductivity of the isotropic natural graphite spheres
This post has been built based on the support of and sponsorship from: Quarto Technical Services, Eatron Technologies and About:Energy
Choi et al [4] look at possible industrial scalable options that improve the graphite performance.
Choi et al [4] look at possible industrial scalable options that improve the graphite performance. Using a mix of large and small particles.
They show the highest rate capability was achieved when the porosity was at a minimum point. Producing the multidirectional increase in Li+ intercalation sites and high amorphous carbon content.
We don’t know the process and engineering that CATL have gone through to engineer the isotropic graphite. Hence we need to be careful about making 2+2 equal to 5. Hence when we find more papers and details we will extend this post. This does show that there is more to achieve in fundamental understanding of the graphite anode.
The 119 Ah cell, which can be used on both BEV and PHEV, guarantees an 80% charge in 15 minutes at room temperature with the support of super electronic network and fast ion ring technology, and empowered by isotropic graphite technology, the 28 Ah cell enables 6C fast charging and 10C recharging [2,3]
References
- Xuan Wu, Xuelin Yang, Fei Zhang, Liangting Cai, Lulu Zhang, Zhaoyin Wen, Carbon-coated isotropic natural graphite spheres as anode material for lithium-ion batteries, Ceramics International, Volume 43, Issue 12, 2017
- Commercial Application Solutions, CATL
- CATL showcases all-scenario solutions and services for commercial applications at IAA Transportation 2022, PR Newswire
- Choi, Y.-J.; Lee, Y.-S.; Kim, J.-H.; Im, J.-S. Optimization of Pore Characteristics of Graphite-Based Anode for Li-Ion Batteries by Control of the Particle Size Distribution. Materials 2023